/* ===================

AX2E (AXESCON XACML 2.0 Engine) is the Java authorization engine, which implements OASIS XACML 2.0 standard.
Copyright (C) 2007 AXESCON LLC

This library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.

This library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
Lesser General Public License for more details.

You should have received a copy of the GNU Lesser General Public
License along with this library; if not, write to the Free Software
Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA


Contact: AXESCON LLC - info{at}axescon.com

 =================== */
package axescon.xacml.model.explain;

/**
 * @author argyn
 *         Date: Oct 17, 2005
 *         Time: 11:18:39 PM
 *         Responsibilities:
 *         contains sentence of result decision like in a stack or list of decision steps
 */
public class Explanation {

    /**
     * points to the head of the decision thread
     */
    DecisionStep start;

    public DecisionStep getStart() {
        return start;
    }

    public void setStart(DecisionStep start) {
        this.start = start;
    }

    public DecisionStep getCurrentStep() {
        return currentStep;
    }

    public void setCurrentStep(DecisionStep currentStep) {
        this.currentStep = currentStep;
    }

    /**
     * points to the current step being evaluated
     */
    DecisionStep currentStep;

    public Explanation() {
        start = new DecisionStep("START.");
        currentStep = start;
    }

    public DecisionStep addChild(String sentence) {
        DecisionStep ret = currentStep.addChild(sentence);
        currentStep = ret;
        return ret;
    }

    public DecisionStep addSibling(String sentence) {
        DecisionStep ret = currentStep.addSibling(sentence);
        currentStep = ret;
        return ret;
    }

    public void addSentence(String sentence) {
        currentStep.append(sentence);
    }

    public void toParent() {
        currentStep = currentStep.parent;
    }

}
